Usefulness of dobutamine stress echocardiography with tissue Doppler imaging for the evaluation and follow-up of patients with repaired tetralogy of Fallot

Background: The longstanding pulmonary regurgitation in patients with repaired tetralogy of Fallot (RTOF) results in right ventricular (RV) failure. The estimation of RV function and reserve in these patients is of great importance, especially for the determination of the proper timing of pulmonary valve replacement. Tissue Doppler imaging (TDI) of the tricuspid annulus has been proved a valuable tool in the evaluation of these patients. Dobutamine stress echocardiography (DSE) in low doses detects the contractility reserve of cardiac myocytes. The aim of our study was to estimate RV reserve in patients with RTOF with the use of DSE and TDI and to examine whether this is related to baseline TDI indices of the tricuspid annulus. Methods: We studied 21 patients with RTOF and 21 age- and gender-matched controls with TDI Doppler at the tricuspid annulus during DSE. TDI measurements were made at baseline and at infusion rates of 10 and 20 mu g . kg . min. Results: Patients with RTOF had lower values of TDI indices at baseline and during dobutamine infusion and smaller dobutamine-induced increase of Sa (Delta Sa) (3.8 +/- 1.2 vs. 10.8 +/- 3.6 cm/sec, P <.001) and Aa (3.5 +/- 2.2 vs. 10.0 +/- 3.2 cm/sec, P<.001). A value of Delta Sa <= 6 cm/sec clearly discriminated patients from controls and could be predicted by values of Sa < 11.5 cm/sec with sensitivity of 95% and specificity of 100%. Conclusions: In patients with RTOF, impaired RV contractile reserve can be documented with TDI of tricuspid annular motion during DSE and is predicted by TDI indices at rest. Its serial estimation may contribute to optimal timing of reoperation.